For me (and for most tourists I would imagine) Oia is the highlight of a trip to Santorini. The town is a hodge podge of alleyways and scenic outlooks over white-washed buildings, blue domed roofs and windmills. I’m seriously not sure if there is a more photogenic town on earth. My advice is simply to spend time wandering; stopping off in the smalls shops and cafes and exploring down quiet cliff-side paths (it might well feel like you’re accidentally wandering in to people’s ‘back gardens’ at times and in honesty I’m not entirely convinced we didn’t). If you fancy a spot of lunch then head down the stairs to Amoudi Bay; where you’ll find a few fish restaurants, a slower pace, and fewer tourists! Hang around in to the evening and book a table for sunset dinner with a view back up to town.